How Should Running Shoes Fit? – Running Shoe Size & Conversion Charts

It’s all about the fit.

I had a running mentor once call me out for my focus on what I call the prettiness factor. You know, the look, cut, angles, material, colors, and of course, how they all played together to make the coolest looking running shoes.

Like many, I think I have a particularly keen eye for the trendiest shoe designs and colors that match my athletic wardrobe. And before you say it, I know plenty of guys that have the same knack for stylish running shoes.

But deep down we know that the prettiness factor has little to do with how the shoe performs while working to reach our running goals. So consider what follows to be a reality check. A guide to understanding just how a new pair of running shoes should fit and how you can identify the best running shoe for your particular needs.

How should running shoes fit?

Let’s settle an age-old debate. Tight is not always right.

Countless individuals spend their childhood and adult lives in ill-fitting shoes with laces that are entirely too tight. This cuts off circulation throughout your foot and ankle and can cause strain amongst the 26 individual bones within your foot.

So, put short, your running shoes should be comfortably snug without adding undue pressure on your toes, heel, midfoot, and top of your foot.

Okay, so now that we got that out of the way, how snug should running shoes actually be?

Elements of a perfectly fitted running shoe;

1. Toe Fit

While your foot is in the shoe and laces up, make sure you can fit a full thumb’s-width between your toe and the tip of the shoe. A half an inch if you’re looking for an exact length. No more, no less. This extra space in the toe-box will allow room to wiggle and prevent them from being jammed into the tip of your shoe.

2. Midsole

The midsole of the shoe should fit like a glove but if you can’t find the perfect fit through this area, err on the side of a bit too loose as you can strategically lace the shoes to be tighter in this area.

3. Heel

The heel should be snug but not constricting and of course, shouldn’t slip around when moving. While trying the shoe on, take a few laps to get a sense of how the heel is going to perform in full stride. 

The last thing you want is to be distracted by a poor-performing heel while you’re on a run, or worse…during a race. One study suggests that running shoes that are equipped with a rigid heel will improve control and reduce the risk of overload injuries.

4. Upper & Laces

We often forget about this element when fitting a shoe, but the upper part of the shoe, including the laces, can cause irritation. Be sure that the upper doesn’t press down on the top of your foot too hard. It should clutch your foot, not suffocate it.

Also, higher lacing is noted to help provide a better shoe performance, reducing the risk of injury.

Rule of Thumb: Size Up Your Running Shoes

It’s likely you know your shoe size off the top of your head. You know what fits, or “feels” right but it’s also likely you’re wearing too small of a shoe.

I know your hesitation. Shoes aren’t cheap and risking the wrong size could mean eating the cost of your, now, used running shoes. But I implore you to take a leap of faith.

Top brands, (we’re looking at you Nike) often run small and your feet will elongate and swell while running. So, bump up half a size on your next pair of running shoes. The additional space will give your feet some wiggle room and it’s unlikely that you’ll suffer from slippage or less stability.

Additional Considerations For Proper Running Shoe Fit

Foot Accessories

From socks, insoles, tape, and ankle braces, there are multiple accessories that can’t be forgotten when finding the right running shoe fit. What it usually boils down to is the amount of additional space you’ll need to allow for all these accessories to be worn comfortably with the shoe.

As noted above, when in doubt, size up.

Also, don’t forget that the material of each foot accessory needs to work well with the material inside the shoe. Slipping, bunching, rubbing, etc… can all occur when you introduce a new accessory. Experiment with what works best for you.

Surfaces

Different running surfaces and distances need to be taken into account when fitting for a running shoe. Cross-country, trail running shoes, track and road runners all likely need a different outsole to help them perform. Understanding what types of materials and traction is needed will help narrow your running shoe options significantly.

Material

Runners are athletes. Athletes sweat. And an athletes’ feet are guaranteed to suffer from increased moisture regardless of the climate you run in. There are multiple hot and cold climate shoe options that utilize different materials, so be conscious of how you can control the temperature with the right decisions on shoe material.

Wide or Narrow Feet

Both wide and narrow feet are very common occurrences, so don’t think you’re alone. It usually just takes a little extra testing to understand which brands offer wide or narrow running shoe options or just naturally have a wide or narrow sizing.

Heel To Toe Drop

Also known as “heel drop”, the heel-to-toe drop is the difference in height between heel and forefoot in the shoe. It’s measured in millimeters, going from 0 to 14mm in running shoes.

Based on a heel drop, shoes are split into 4 categories: 

1. Zero drop (0mm), 
2. Low drop (1-4mm), 
3. Mid drop (5-8mm), and
4. High drop (8+ mm) shoes. 

The most common heel drop is 10mm.

You can read more about optimizing your heel drop for training here, but for now, just know that heel drop can factor into the comfort, type of terrain and injury prevention help you may be seeking in your perfect shoe.

Alternating Shoes

Many runners alternate between shoes based on the varying factors of their training regimen. From specific types of runs or distances, extra cushioning options, walking shoes, etc… 

What’s more, is that every mile of wear and tear you put on a shoe is a mile less on the lifespan of a shoe. Subbing new shoes in and out is a strategy we see many runners develop over time.

Foot Growth & Changes

Feet grow. 

And your feet change as you become more or less active over time. So make it a habit to reassess your foot sizes, training needs, and common ailments to ensure you find the right pair of shoes.

Children, Teens, & Young Adults

Foot growth depends on the age of the child and their growth often comes in spurts. For this reason, you’ll want to monitor how their shoes fit to prevent injury and developmental issues. 

Here are a few guidelines to follow, based on the age of your child.

Risks of Running In Ill-Fitting Shoes

Finally, a word to the wise. Running shoes that don’t fit can result in a myriad of problems. What types of problems you ask? Here’s just a shortlist of preventable issues;

• Bunions
• Blisters
• Calluses
• Ingrown Toenails
• Numbness
• Soreness
• Poor Circulation
• Athletes Foot
• Hammertoe
• Nerve Damage
• Ankle Sprains
• Overpronation
• Underpronation / Supination
• Shin Splints
• Calf Strains
• Heel Spurs

So whatever your favorite running activity is the last thing you want is to be sidelined! Keep your feet healthy and happy by taking a little extra time to understand how running shoes should fit and how to identify the best options for your next purchase. We’ve made it easy to find the best running shoe options with a number of buying guides and hundreds of individual running shoe reviews.

How to measure the length and width of your feet.

To ensure you order the right running shoe size, you’ll want to follow these instructions. Here’s what you’ll need; 2 sheets of paper. 1 marker. 1 measuring tape or ruler. Optional: A friend to help. Or skip the at-home measuring altogether and stop at your local shoe store. Their foot measuring tool, AKA the Brannock Device, will give you a solid measurement and cost you nothing. 

1. While wearing the socks you typically run in, stand up on each sheet of paper, distributing your weight evenly.
2. While keeping the pen as straight as possible, trace each outline of your foot. This is where a friend may come in handy. 
3. To measure the length of your foot, measure from the heel to the longest toe.
4. Next, measure the length of your other foot. You’ll want to take the length of your two feet and compare it to the charts below.
5. Generally, we recommend going one, half size up, as some shoe brands run small and your feet will swell and elongate while running. 
6. To measure the width of your foot, measure the widest part of your foot. 
7. Next, measure the width of your other foot. You’ll want to take the wider of your two feet and compare it to the charts below.

Running Shoe Size Conversion Charts (United States, United Kingdom & European)